I finished Mockingjay this week, and I don't think I can write about it without spoiling the series, at least, if not the book itself. So this review is only safe if you've read The Hunger Games and Catching Fire, or at least don't mind knowing something about how they end, and really, there are some hints to what happens in Mockingjay, too.
I've heard a lot of different opinions about which of the last two books is better (I've never met anyone who didn't think The Hunger Games was the best of the three). I personally liked Mockingjay better than Catching Fire. I found the premise of the second book to be a little "hey, let's do this again," though in the broader picture I know that's not true.
And I found the ending to be a little confusing--I got some of the characters mixed up (Johanna and Enobaria, specifically, are sometimes conflated in my memory), and I never really figured out what was going on, who was double crossing who, etc. One thing I really like about this series is that Katniss is often in the dark, or confused, or doesn't have enough information to make a good decision--this is a lot more realistic than a lot of adventure stories. But sometimes I find myself equally confused, and it doesn't always get cleared up to my satisfaction.
Another level of realism that I like is the PTSD that all these poor people suffer from. It makes horrible sense, doesn't it? How could you not be messed up by an experience like that? Fiction generally wants me to believe that action heroes are just fine--they routinely take injuries that would drop real people in their tracks without slowing their pace. The most heroic thing a real-life hero has ever done--rescued ten soldiers from an ambush or racing out of a burning building carrying a child--is what a fictional character does in the first few pages to set them up for the real heroics later on. So the fact that kill-or-be-killed messes with these poor kids' heads is really well appreciated.
What I liked about Mockingjay, I think, was just what I can picture some people not liking--the politics. I appreciated that we not only got to watch the revolution but to agonize over how it would end. If you think about most of the real revolutions in history, they were bloody and violent and the resulting government was often crappy in either similar or opposite ways to the overthrown government. (The American Revolution is a bit of an exception, but our oppressors had the option of retreating back to their own country, which is not usually the case.) So I think that the power Katniss has and her odd, detached position that allows her to look at things somewhat objectively is a really interesting place for observation and thought.
There are some obvious and some less-than-convincing plot points, which I won't bother with because I don't want to spoil it and because they're not that important. The places that the story goes are thrilling, compelling, and tragic; the mechanisms involved in getting everyone in place are sometimes a little contrived. But there was a scene at the end--the scene with the cat, for those of you who've read it--where I really cried. So there's that.
Then there's the real question: are you on Team Peeta or Team Gale? I have an opinion on that one, too, but I can't talk about it, again, without spoiling. But tell me which one you were rooting for--at any point in the books--in the comments, and we'll keep all you people who are still waiting in a 400-person library queue out of the comments till you're done. Don't worry; I'm returning my copy tomorrow, so you'll move up a slot on the list.